Present day commercial aircraft of a passenger carrying type utilize onboard air conditioning/distribution systems for regulating air temperature of passenger cabin and flight deck compartments. These systems employ temperature sensors in the compartments which sense air temperature therein and communicate this information to a system controller. An air conditioning pack or unit in the system produces a flow of cool, conditioned air at a certain temperature. The system controller causes this conditioned air to be communicated to either the flight deck or that zone in the passenger cabin which requires the lowest temperature air. Generally, this will be the flight deck since in most aircraft the flight deck has more window area which consequently produces greater solar heating. Remaining zones or areas in the passenger cabin, which require warmer air, are supplied with the same air produced by the air conditioning pack but which is warmed a certain amount by the addition of hot bleed air from an engine. In the past, addition or mixing of bleed air was controlled by a plurality of trim air control valves. Normally, a separate trim air control valve is required for each separate temperature control zone in the cabin and flight deck compartments. By way of example, a passenger cabin may have as many as three temperature control zones, meaning a total of four trim air control valves is needed, one for the flight deck and three for the passenger cabin. Each valve has a relatively complicated construction. For example, each has its own electric motor, speed reduction mechanism, sensors and switches. The complexity of these valves add significantly to aircraft weight and to the complexity of aircraft operation and maintenance. The purpose of the present invention, therefore, is to provide an improved trim air control valve apparatus that overcomes these disadvantages.